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Merge pull request #32 from ittner/fix-xml-escaping

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Fix escaping of XML text and attributes
This commit is contained in:
Jack Moffitt
2013-03-29 08:04:25 -07:00
parent 5f174b646f c0b1e5b7fe
commit 4ad21c9283
1 changed files with 68 additions and 3 deletions
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71
src/stanza.c
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@@ -206,6 +206,64 @@ int xmpp_stanza_is_tag(xmpp_stanza_t * const stanza)
return (stanza && stanza->type == XMPP_STANZA_TAG);
}
/* Escape a string with for use in a XML text node or attribute. Assumes that
* the input string is encoded in UTF-8. On sucess, returns a pointer to a
* buffer with the resulting data which must be xmpp_free()'d by the caller.
* On failure, returns NULL.
*/
static char *_escape_xml(xmpp_ctx_t * const ctx, char *text)
{
size_t len = 0;
char *src;
char *dst;
char *buf;
for (src = text; *src != '\0'; src++) {
switch (*src) {
case '<': /* "&lt;" */
case '>': /* "&gt;" */
len += 4;
break;
case '&': /* "&amp;" */
len += 5;
break;
case '"':
len += 6; /*"&quot;" */
break;
default:
len++;
}
}
if ((buf = xmpp_alloc(ctx, (len+1) * sizeof(char))) == NULL)
return NULL; /* Error */
dst = buf;
for (src = text; *src != '\0'; src++) {
switch (*src) {
case '<':
strcpy(dst, "&lt;");
dst += 4;
break;
case '>':
strcpy(dst, "&gt;");
dst += 4;
break;
case '&':
strcpy(dst, "&amp;");
dst += 5;
break;
case '"':
strcpy(dst, "&quot;");
dst += 6;
break;
default:
*dst = *src;
dst++;
}
}
*dst = '\0';
return buf;
}
/* small helper function */
static inline void _render_update(int *written, const int length,
const int lastwrite,
@@ -236,6 +294,7 @@ static int _render_stanza_recursive(xmpp_stanza_t *stanza,
xmpp_stanza_t *child;
hash_iterator_t *iter;
const char *key;
char *tmp;
written = 0;
@@ -244,7 +303,10 @@ static int _render_stanza_recursive(xmpp_stanza_t *stanza,
if (stanza->type == XMPP_STANZA_TEXT) {
if (!stanza->data) return XMPP_EINVOP;
ret = xmpp_snprintf(ptr, left, "%s", stanza->data);
tmp = _escape_xml(stanza->ctx, stanza->data);
if (tmp == NULL) return XMPP_EMEM;
ret = xmpp_snprintf(ptr, left, "%s", tmp);
xmpp_free(stanza->ctx, tmp);
if (ret < 0) return XMPP_EMEM;
_render_update(&written, buflen, ret, &left, &ptr);
} else { /* stanza->type == XMPP_STANZA_TAG */
@@ -258,8 +320,11 @@ static int _render_stanza_recursive(xmpp_stanza_t *stanza,
if (stanza->attributes && hash_num_keys(stanza->attributes) > 0) {
iter = hash_iter_new(stanza->attributes);
while ((key = hash_iter_next(iter))) {
ret = xmpp_snprintf(ptr, left, " %s=\"%s\"", key,
(char *)hash_get(stanza->attributes, key));
tmp = _escape_xml(stanza->ctx,
(char *)hash_get(stanza->attributes, key));
if (tmp == NULL) return XMPP_EMEM;
ret = xmpp_snprintf(ptr, left, " %s=\"%s\"", key, tmp);
xmpp_free(stanza->ctx, tmp);
if (ret < 0) return XMPP_EMEM;
_render_update(&written, buflen, ret, &left, &ptr);
}